Variable-pitch propeller



D. F. 200K.

VARIABLE PITCH PROPELLER.

APPLICATION FILED AUG.1B,19I9.

1N VENTOR DKZOOK.

Patented May 9, 1922.

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VARIABLE PITCH PROPELLER.

APPLlCATlON FILED AUGJB, 1919.

1,415,756. Patentd May 9. 1922.

2 SHEETS-SHEET 2.

INVENTOR ..D.EZO0K. BY M 44. 3 0

A TTORNEYS but adding much to the DAVID F. ZOOK, OF PASADENA, CALIFORNIA.

VARIABLE-PITCH PROPELLER.

Specification of Letters Patent.

Patented May 9, 1922..

Application filed August 18, 1919. Serial No. 318,255.

To all whom. it may] concern Be it known that I, DAVID F. ZOOK, a 'Cltlzen of the United States, and a resident of the city of Pasadena, in the county of Los Angeles and State of California, have invented a new and useful Improvement in a Variable-Pitch Propeller, of which the following is a variable pitch propellers, and it consists in the combinations, constructions and arrangements herewith described and claimed.

An object of my invention is to. provide a propeller for aeroplanes which has blades so arranged that they may be turned to vary the pitch while the areoplane is in flight.

A further object of my invention is to provide an aeroplahe propeller in which the pitch of the propeller may be varied, so that one pitch may be used, as, for instance, when taking oil and climbing and another for high speed and altitude work.

A further object of my invention is to provide a variable pitch propeller with which a slower speed motor may be used, thus gaining not only the screw efficiency,

life of the engine.

Other objects and advantages will appear in the following specification, and the novel features of the invention will be particularly pointed out in the appended. claim.

y invention isillustrated in the accom panying drawings, forming part of this application, in which- Figure 1 is a View showing the general assembly of' the propeller mechanism, and the means for operating the same,

Figure 2 is a view partly in section of a bracket,

Figure 3 is a view of the bracket at right angles to Figure 2,

Figure 4 is a sectional view through a propeller blade, showing its 'relationwith respect to a supporting tube,

Figure 5 is a view of a slidable sleeve, a portion being shown in section, and

Figure 6 is a detailed view showing the crank connections for turning the propeller blades. 7

In carrying out my invention, I provide a light metal casting which is preferably made of aluminum which has the shape shown in Figures 2 an: This casting, as it will be observed, consists of a central housing 1 having laterally extending integral sleeves 2 and 3, these sleeves being braced full, clear, and exact description. y lnventlon relates to improvements 111 Figure 1) with a fuselage by flanges 4-. The bracket thus fitted onto the squared end of the shaft 5, being locked thereon by a nut 6. 7

Two propeller blades 7 and 8 are secured to'extensions 35 of tubes 9 and 10 respec tively', which are rotatively disposed in the sleeves 2 of the bracket. Crank arms 11 and 12 are bolted rigidly to the inner ends of the tubes 9 and 10 wlthin the housing 1, as shown in Figure 6. A sleeve 13 is feathered to the shaft 5 by feathers 14, so as to slide along the shaft, but to rotate with it. It is provided with a circular thrust member 15 having braces 16. This thrust member is disposed between anti-friction balls 17 carried by a thrust ring 18. The latter is connected with a yoke 19 having an arm 20 connected by means of a link 21 (see 22 and a second. arm 23, which is connected by a ball and socket joint 24L with a screw shaft 25, which passes through an instrument board 26 and which is operated by a handle 27 on an adjusting wheel 28. The screw 25 is suitably braced at 29.

The sleeve 13 is provided with projecting shoulders 30 which are connected by means of links 31 and 32 with the ends of the crank arms 11 and 12 respectively.

From the foregoing description of the various parts of the device, the operation thereof may be readily understood. While the propeller inself is rigidly fixed in position, the sleeve is sli-dahle along the shaft, and its iosition is under control of the pilot.

he esires to change the pitch of the blades, he turns the handle 27, thus moving the screw 25 longitudinally and shifting the lever, formed by the arms 20 and 23 and the yoke 19, forwardly or backwardly, in ac cordance with the direction in which-the handle 2? is turned. The yoke 19 is pivotally connected at 33 with the thrust ring 18, so that the latter moves the sleeve 13 formed is propeller means of Mill forwardly or backwardly, and through the lid the sleeve 2. The side edges of theblade are therefore equi-distant from the central axis of the tube, thereby insuring a perfect balance' The arrangement disclosed offers an efficient means for adjusting the tube of either blade independently of' the other one. To this end, either of the threaded links 31 or 32 may turn to make theeffective length of the link greater or less, thereby turning the crank arm a: corresponding distance and bringing the blade to the angle desired.

I claim:

A variable pitch propeller comprising a power driven shaft,a metal housing having a plurality of sleeves radially extending therefrom, a short sleeve centrally located with respect to said housing and extending outwardly therefrom, said last named sleeve arranged to engage said shaft and to support said housing thereupon at its outermost end, whereby the opposite side of said housing is unobstructed by supporting means and the interior thereof made readily accessible, tubular shafts disposed in said radial sleeve and arranged to projectbeyond both ends thereof, propellerb-lades carried by said tubular shafts at the outer ends of said sleeve, and means communicating with the opposite ends of said tubular shafts within said'housing for turning said blades simultaneously at will, said radial sleeves being relatively longer than said propeller blades.

DAVID F. ZOOK. 

